This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The objective of this project is to find better and safer antiviral drugs to treat HIV infection. Simian immunodeficiency virus infection of newborn and infant macaques is a useful animal model of human AIDS to evaluate novel antiviral drugs. Previously, we initiated studies to evaluate the long-term therapeutic and toxic effects of tenofovir (9-[2-(phosphonomethoxy)-propyl]adenine;PMPA).